sony cheated with their customers

I am having the following issues with my sony xperia c :

1) Very low space to install applications on phone memory : Apparently sony claims to provide us with 4GB worth of memory to install
applications ,but the actual available space comes down to approximately 300 MB .Here’s how – out of 4GB, 2.20GB is aviable to user
where 1.20GB as internal memory to store files, images, songs extra and rest 0.98 as Device Memory in which approx 700MB contains pre installed and i got only 300MB to install app.

So, i feel i have been cheated by Sony and i have made a big mistake after buying this phone.

2) Complacent service centres- My phone is in accidental warranty and i have been to the service centre a couple of times asking
them to replace my phone’s broken back cover.But everytime they ask me to submit my phone for atleast ten days.They are also not
providing any kind of stand on phone.Who submits their phone for ten days for just a back cover.They can easily order the part from
the company and replace it then and there.
Very irritated by their service.